High-performance N₂-to-NH₃ fixation by a metal-free electrocatalyst

Area of Science:

• Materials Science
• Electrochemistry
• Green Chemistry

Background:

• The Haber-Bosch process, while crucial for ammonia synthesis, is energy-intensive and a significant source of CO2 emissions.
• Developing alternative, sustainable ammonia synthesis methods is critical for reducing environmental impact.
• Electrocatalytic nitrogen reduction under ambient conditions presents a promising green alternative, but requires highly efficient electrocatalysts.

Purpose of the Study:

• To report a novel, metal-free electrocatalyst for nitrogen (N2) reduction to ammonia (NH3) under ambient conditions.
• To investigate the efficacy of mesoporous boron nitride (MBN) as an electrocatalyst for sustainable ammonia synthesis.
• To evaluate the performance and durability of the MBN electrocatalyst.

Main Methods:

• Synthesis of a mesoporous boron nitride (MBN) material.
• Electrochemical testing of MBN for N2 reduction reaction in an aqueous electrolyte (0.1 M Na2SO4).
• Performance evaluation including ammonia formation rate and Faradaic efficiency at a potential of -0.7 V vs. reversible hydrogen electrode (RHE).

Main Results:

• The MBN electrocatalyst achieved an ammonia formation rate of 18.2 μg h-1 mgcat.-1.
• A Faradaic efficiency of 5.5% for ammonia production was observed at -0.7 V vs. RHE.
• The MBN electrocatalyst exhibited strong long-term electrochemical durability during the N2 reduction reaction.

Conclusions:

• Mesoporous boron nitride (MBN) is an effective metal-free electrocatalyst for ammonia synthesis from N2 under ambient conditions.
• The MBN catalyst offers a promising, sustainable alternative to the conventional Haber-Bosch process.
• Further research into MBN-based catalysts could lead to more efficient and environmentally friendly ammonia production technologies.